The present invention is generally directed to oil filters, and more particularly to a device for removing the filter medium from the spool of an oil filter for inspection purposes.
During a 100 hour or annual inspection on a piston aircraft, one of the accepted practices in the industry is that the oil is changed and the spin on oil filter is replaced. In addition, the old filter canister is cut open and the spool containing the filter medium is inspected for any metal particles which would indicate a potential internal failure of main bearings or other moving parts internal to the engine crankcase.
The most popular brand of aviation oil filter is the Champion(copyright) brand. The filter canister is cut open, using one of the many oil filter cutters available on the market today. The spool or core which holds the filter medium is then removed from the canister and inspected for the presence of metal particles. In order to adequately inspect for these metal particles, the paper filter medium must be removed from the spool.
At the present time, the only way to do this is to grab the spool containing the filter medium and using a long thin knife, such as a utility knife, to cut each end of the paper filter medium all of the way around the spool close to where it is glued to the central hub of the metal spool. The filter medium can then be removed from the metal spool and stretched out and inspected for contamination. This is a very difficult task taking into consideration that the spool and filter medium is covered with oil and is very slippery. The knife can easily slip and cut the mechanic. Also, due to its construction, the spool has sharp edges which can injury the mechanic as well.
The present invention overcomes the aforementioned difficulties associated with removing the filter medium from the spool of an oil filter. The device of the present invention is designed to cut the paper filter element at each end of the metal spool after it is removed from its canister. The filter medium can then be removed from the spool and stretched out for inspection of contamination. This tool will cut the medium on all Champion brand aviation oil filters as well as all Challenger brand aviation oil filters. Until now this task was performed by hand at significant risk to the aircraft mechanic of being cut.
The device of the present invention is intended to be held in a vice, or alternatively, it can be screwed to a workbench. Once the oil filter can is cut open, the filter spool containing the filter medium is removed from the canister. There is a strip (or clip) of metal connecting each end of the paper filter medium together on the spool. The strip is twisted or broken loose with a pair of pliers at each end of the spool to allow a path for the cutter blade to cut the filter medium. The spool is then slipped into a spool holder/crank and a thumbscrew is tightened to lock it in place. This assembly is inserted into a spindle assembly so that three roller bearings contact the outer circumference of the holder/crank. The holder/crank and spool can then be rotated. The other end of the spool has a hole in it, which fits onto an aluminum shaft spindle allowing that end to be stabilized when rotating.
A cutter assembly can be moved left and right along the entire length of the spool on a guide rod. The cutter assembly has a safety cover that is spring loaded to the closed position. When the operator decides to cut the filter medium, the cutter assembly cover is held by the black plastic handgrip and pulled toward the operator exposing the blade. At that time, the blade can be brought down to bear onto the filter medium as the other hand rotates the holder/crank by means of a crank handle. It takes very little time to actually make the cuts. Two cuts are made into the filter medium (one at each end) around its entire circumference. The filter medium is then removed as one complete piece and stretched out on a workbench for examination.
Features:
The present invention comprises a unique way to hold the oil filter spool.
The roller bearings provide a way to stabilize the end of the spool that is held by the holder/crank.
The sliding safety handle reduces any hazard to the operator while working near the tool
The present invention saves considerable time in the process of removing the filter medium from the spool.
The present invention is adjustable so as to accept all Champion and Challenger brand aviation oil filters.
The present invention is precision machined of 6061-T6 aluminum.
Advantages:
The present invention is unique in that it provides a safe means to hold the oil filter spool for cutting.
The present invention makes a tough job easier and promotes examining the filter media more closely.
The present invention reduces the hazard and danger of being cut while cutting the filter medium.
The present invention saves time. It takes less than a minute to cut the filter medium at both ends of the spool.
The cutting operation is less tedious to perform.
The present invention cuts more uniformly and completely without any contamination to the filter medium.
In accordance with a preferred embodiment of the invention, a device for removing the filter medium from the spool of an oil filter, the spool having a first end having a hole and an opposite second end. The device has a spindle assembly having (1) a spindle which is shaped and dimensioned to receive the hole in the first end of the spool, (2) a plurality of bearings, and (3) a cutter. The device further includes a holder/crank which is shaped and dimensioned to receive the second end of the spool. The holder/crank has (1) a retainer for fixedly holding the spool in the holder/crank, a circular rim, and (3) a handle for rotating the holder/crank. The second end of the spool may be connected to the holder/crank, the spool and holder/crank may be inserted into the spindle assembly so that the spindle engages the hole in the first end of the spool and the rim engages the plurality of bearings. The cutter is then brought to bear against the filter medium, and the handle of the holder/crank rotated so that a circumferential cut is made in the filter medium.
In accordance with an important aspect of the invention, the spindle is longitudinally movable and lockable with respect to the plurality of bearings.
In accordance with an important feature of the invention, the spindle has a circular hole engaging portion which has a plurality of stagger-stepped diameters for receiving spool holes of different sizes.
In accordance with another important aspect of the invention, the spindle has a stop for aligning the spool with the spindle and the rim with the plurality of bearings.
In accordance with another important feature of the invention, the spindle assembly includes a guide rod. The cutter is rotatably connected to the guide rod, and can be longitudinally moved along the guide rod.
In accordance with another important aspect of the invention, the cutter has a selectively retractable hood which covers a cutting blade.
In accordance with another important feature of the invention, the spindle assembly has a downwardly projecting flange to accommodate installation in a conventional vice. Alternatively, the flange may be removed and the spindle assembly may be rigidly mounted on a work bench or table.
In accordance with another aspect of the invention, the holder/crank includes a pocket which is shaped and dimensioned to receive the second end of the spool.